Good for you!
As JeffS said in above post, it would be different if the seller had an emergency, and packages would be late getting mailed. That's completely understandable. BUT (and it's very unfortunate) some people will use any and every excuse to get out of a winning bid and it's not fair to you. Uploading photos, writing listings, fees, etc. That's your time & $ being wasted.
Just do not do a mutual withdrawl-make sure the buyer gets a strike. You'll have to leave the dispute open for 8 days, I believe, or until the buyer responds (pls check this, I'm not 100% positive)then close and give them a strike. This way you'll be sure to get your fees back.